1. Field of the Invention
The present invention relates to an SLR camera equipped with a quick-return mirror that swings between a viewing position and a retracted position, and in particular, relates to a mirror drive apparatus incorporating a brake mechanism for the quick-return mirror.
2. Description of the Related Art
The quick-return mirror (hereinafter referred to simply as a mirror) of an SLR camera swings between a viewing position, in which light traveling from a photographing lens is incident on the quick-return mirror and reflected thereby toward a viewfinder optical system, and a retracted position, in which the light traveling from the photographing lens is allowed to be incident on film or an image pickup device such as an image sensor without being reflected by the mirror. In 35 mm-format SLR compact cameras, it is typically the case that the mirror is simply made to bump against a mirror-up stopper to stop thereat when the mirror swings up from the viewing position to the retracted position; however, in medium format SLR cameras, the shock produced upon the mirror being retracted to the retracted position from the viewing position is great because the inertia of the mirror is great. Accordingly, a medium format SLR camera equipped with a mirror-up brake mechanism to reduce such a shock is known in the art, e.g., Japanese Unexamined Patent Publication No. S57-70524. On the other hand, although not shown in Japanese Unexamined Patent Publication No. S57-70524, the movement of the mirror from the viewing position to the retracted position is typically caused by a spring force, and the movement of the mirror from the retracted position to the viewing position is typically caused by an operation of a motor.
However, the conventional mirror brake mechanism is provided independently of the motor-driven mirror drive apparatus, so that the system which links up the mirror brake mechanism with the mirror drive apparatus, and the adjustment therefor are complicated; moreover, this structure is disadvantageous in regard to miniaturization. In addition, although the invention disclosed in the above-mentioned Japanese Unexamined Patent Publication No. S57-70524 does not disclose any mirror brake release mechanism, the mirror brake is actually released with the use of a complicated transmission mechanism, which is disadvantageous in regard to reliability and production cost. Additionally, in the mirror brake mechanism disclosed in Japanese Unexamined Patent Publication No. S57-70524, a sector gear is integrally formed with a mirror seat (which holds the mirror) to extend toward the rear of the rotational shaft of the mirror seat, and a brake mechanism is installed in association with the sector gear. Due to this structure, an installation space for the mirror brake mechanism is required behind the mirror (mirror box), which is disadvantageous in regard to miniaturization of the camera.